Potential of the combination of acid and alkaline proteases on amino acid digestibility in broiler diets.

This study aimed to evaluate the effects of including a blend of acid and alkaline proteases in broiler diets on performance parameters, nutrient digestibility, and intestinal morphology. A total of 180 chicks were divided into the following groups: Positive Control (PC), Negative Control (with 8% reduction in crude protein-NC), and NC + blend proteases (BP) at 125 g/t (BP125). On days 1 and 21, the broilers and the feed were weighed for performance analysis, and a digestibility test was performed from days 17 to 21. The highest body weight and weight gain were observed in the broilers of the PC and BP125 groups (P = 0.001). The addition of protease to the diet (BP125) increased the ADC of crude protein, which was statistically similar to the PC group; both were higher than those observed in the NC group. We observed that the BP125 group had more excellent digestibility of the amino acids of serine (P = 0.032), threonine (P = 0.050), valine (P = 0.042), methionine (P = 0.050), cysteine (P = 0.012), arginine (P < 0.001) and tryptophan (P = 0.05) when compared to NC; but similar to PC group. It was also possible to observe a better villus and crypt ratio when protease was used in a low-protein diet (P = 0.05). These findings suggest that protease supplementation improves nutrient utilization and performance in low-protein diets.